1. Field of the Invention
This invention relates to a process and apparatus for applying chilled finely divided particles to the surface of a large metal object having crevices or pores therein. More specifically, it relates to a method for chilling and applying electrostatically charged particles to such an object. Still more specifically it relates to a method of rotating and maintaining the large object at the desired raised temperature during the application of the chilled particles. Still more specifically it relates to apparatus for effecting this process.
2. Description of the Prior Art
U.S. Pat. No. 3,279,936, issued to Clarence W. Forestek on Oct. 18, 1966, is directed to the treating of metal surfaces having crevices or pores therein with perfluorocarbon polymer particles so as to deposit such particles into the pores. By having the metal at a raised temperature to enlarge the pores and the particles chilled to contract them, the particles are interlocked in the pores when the particles and the metal come to an equilibrium temperature whereby the particles are expanded and the pores contracted.
U.S. Pat. No. 4,051,275 issued on Sept. 17, 1977 was also granted to Clarence W. Forestek and is directed to applying such chilled particles in a fluid stream carrying finely divided particles applied at a pressure of 30-120 psi to compact previously deposited particles and thereafter depositing additional particles in the space freed by the compaction, said additional particles being a temperature at least 100.degree. F. below the temperature of the metal surface so that these additional particles will also be locked into the fissures upon reaching equilibrium temperature.